Safia Bibi, Waquaruddin Ahmed, Syed Ejaz Alam.
Comparison of rapid test with ELISA for the detection of hepatitis B surface antibodies.
Pak J Med Res Jan ;53(3):60-2.

Objectives: To compare the sensitivity and specificity of a rapid ICT test with ELISA for the detection of Hepatitis B surface antibody. Study type, settings and duration: Cross sectional comparative study conducted at PMRC Specialized Centre for gastroenterology and hepatology JPMC, Karachi from April 2012 - March 2013. Materials and Methods: A total of 206 apparently healthy adults were selected from a rural community. After taking informed consent, 5ml blood was collected sera separated and tested for hepatitis B surface antibody (anti-HBs) by a rapid immuno-chromatographic test developed by Korea (Humasis) and ELISA simultaneously. As per manufacturer’s guidelines, the rapid ICT test is interpreted as positive if antibody titers are > 30mIU/ml and negative if the titers are < 30mIU/ml. For ELISA, the CDC interprets antibody titers > 10mIU/ml as positive or protective and < 10mIU/ml as negative and recommends a booster dose. The results of ELISA (gold standard) were compared with rapid test using SPSS version 17.0. Results: Out of 206 sera, using ELISA, anti-HBs was positive in 91(44.2%) sera and negative in 115(55.8%) sera. Using ICT, anti-HBs was positive in 85(41.3%) and negative in 121(58.7%) and the sensitivity and specificity of rapid test ICT was 83.5% and 92.2% respectively with overall accuracy of 88.5%. These figures fell to 70.8% sensitivity and 94.6% specificity with 81.5% accuracy when CDC cut off of 10mIU/ml was used. The ICT kit gave good results in samples having high titers (> 100mIU/ml) but had a limited sensitivity for cases having titers between 10mIU/ml-100mIU/ml, thus limiting its use and creating unnecessary demand for booster dose of vaccine. Conclusion: The rapid ICT for antiHBs is not as sensitive as ELISA but can still be used for rapid decision making especially in OPD setups and remote areas.

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